# ITM: Index Target based on natural mortality rate In DLMtool: Data-Limited Methods Toolkit

## Description

An index target MP where the TAC is modified according to current index levels (mean index over last number of years determined by natural mortality (M)) relative to a target level.

## Usage

 1 ITM(x, Data, reps = 100, plot = FALSE) 

## Arguments

 x A position in the data object Data A data object reps The number of stochastic samples of the MP recommendation(s) plot Logical. Show the plot?

## Details

The TAC is caluclated as:

\textrm{TAC}_y = \textrm{TAC}_{y-1} δ I

where δ I is the ratio of the mean index over 4\frac{1}{M}^{1/4} years to the reference index ([email protected]).

The maximum fractional change in TAC is determined by mc, defined as mc = \textrm{max}≤ft(\frac{5 + 25M}{100}, 0.2\right)

## Value

An object of class Rec with the TAC slot populated with a numeric vector of length reps

## Required Data

See Data for information on the Data object

ITM: Ind, Iref, MPrec, Mort

## Rendered Equations

See Online Documentation for correctly rendered equations

T. Carruthers

## Examples

 1 ITM(1, Data=DLMtool::SimulatedData, plot=TRUE) 

DLMtool documentation built on Dec. 6, 2019, 9:06 a.m.